Lennox Pulse Furnace Maintenance

MikeAtl

I am looking to replace the air flapper/diaphragm assembly on a Lennox Pulse furnace (Model G14Q4-80-20 installed 1987).

I have a couple of parts lists with different part numbers (PNs) for the air diaphragm assembly, including LB-49997CB, LB-45918CD, LB-45918CE, or LB-45918CT. I have also seen these listed generally by PN 68F89. All look similar in the pics I've found online. Obviously, parts for this furnace are hare to come by. My question is whether there is a significant difference between these PNs and if any are interchangeable.

Also, I am aware of the issues with this furnace and its need for replacement. Unfortunately, my property will probably be demolished in the next few years so I am just trying to limp it through a couple more seasons... replacement is not an option.

Thanks in advance.

Big Ed_4

Call Lenox tech support to verify ....

wmgeorge

As you might already know those had a recall on the heat exchanger leaking, they used the wrong flux on brazing the tubes. Mine was in the recall and I got a new heat exchanger, my unit was installed in 1983 or about. They had a bunch of new exchangers made and then stopped production. When those ran out they gave a big, big discount for a new furnace. You might call with your serial number to check, not sure what they are doing at this time, pretty late in the game.

GW

Supposed to pressure test these every 4 years. It’s a positive pressure HX so it there’s a problem you need  to stop using the furnace. You need a certain set up to test (Lennox parts-tools)

wmgeorge

Or have a good working CO detector that is how mine was found. In any event the OP needs to be made aware of the issue, like I said before that's old news by now.

pecmsg

wmgeorge said:

Or have a good working CO detector that is how mine was found. In any event the OP needs to be made aware of the issue, like I said before that's old news by now.

Good working are not good enough

Low Level CO detectors that will alarm well before the 70PPM 1- 3-hour delay UL listed models!

wmgeorge

pecmsg said:

wmgeorge said:

Or have a good working CO detector that is how mine was found. In any event the OP needs to be made aware of the issue, like I said before that's old news by now.

Good working are not good enough

Low Level CO detectors that will alarm well before the 70PPM 1- 3-hour delay UL listed models!

Mine are all digital and read out in PPM, like I said before that is how I found mine so I say it was good, wouldn't you?

pecmsg

wmgeorge said:

pecmsg said:

wmgeorge said:

Or have a good working CO detector that is how mine was found. In any event the OP needs to be made aware of the issue, like I said before that's old news by now.

Good working are not good enough

Low Level CO detectors that will alarm well before the 70PPM 1- 3-hour delay UL listed models!

Mine are all digital and read out in PPM, like I said before that is how I found mine so I say it was good, wouldn't you?

Are they UL listed?

pecmsg

https://www.carbonmonoxidekills.com/carbon-monoxide-detectors/ul2034-american/

The American Standard – UL2034
This standard was implemented in the early nineties to cover products being supplied and used in the American (and North American) markets. It has also been subject to a number of amendments over the years (1997,1998, 2001).

Products officially approved to this standard must be clearly marked with the UL symbol (perhaps add picture of UL symbol to web page).

Main alarm requirements :

at 30ppm CO, the alarm must not activate for at least 8 hours
at 70ppm CO, the alarm must not activate before 60 minutes but must
activate before 240 minutes
at 150ppm CO, the alarm must not activate before 10 minutes but must
activate before 50 minutes
at 400ppm CO, the alarm must not activate before 4 minutes but must activate before 15 minutes

15 PPM zero minuets is the threshold when fire fighters are required to use SCBA equipment.

wmgeorge

pecmsg said:

wmgeorge said:

pecmsg said:

wmgeorge said:

Or have a good working CO detector that is how mine was found. In any event the OP needs to be made aware of the issue, like I said before that's old news by now.

Good working are not good enough

Low Level CO detectors that will alarm well before the 70PPM 1- 3-hour delay UL listed models!

Mine are all digital and read out in PPM, like I said before that is how I found mine so I say it was good, wouldn't you?

Are they UL listed?

Perhaps but the one that found the issue was years and years ago way before I retired in 2007 and it worked. I am wondering what difference does it make today?? For the average homeowner I would say just having a CO detector and smoke detectors in the house saves lives, do you not agree? Most consumer level CO alarms go off way lower than 70 ppm, some as low as 20.

Oh and I helped teach the CO awareness classes before I retired.

https://www.cpsc.gov/Safety-Education/Safety-Education-Centers/Carbon-Monoxide-Information-Center/Carbon-Monoxide-Questions-and-Answers

pecmsg

wmgeorge said:

pecmsg said:

wmgeorge said:

pecmsg said:

wmgeorge said:

Or have a good working CO detector that is how mine was found. In any event the OP needs to be made aware of the issue, like I said before that's old news by now.

Good working are not good enough

Low Level CO detectors that will alarm well before the 70PPM 1- 3-hour delay UL listed models!

Mine are all digital and read out in PPM, like I said before that is how I found mine so I say it was good, wouldn't you?

Are they UL listed?

Perhaps but the one that found the issue was years and years ago way before I retired in 2007 and it worked. I am wondering what difference does it make today?? For the average homeowner I would say just having a CO detector and smoke detectors in the house saves lives, do you not agree?

Oh and I helped teach the CO awareness classes before I retired.

https://www.cpsc.gov/Safety-Education/Safety-Education-Centers/Carbon-Monoxide-Information-Center/Carbon-Monoxide-Questions-and-Answers

It gives a false sense of security! At 70 PPM the alarm starts the timer:

a) the level drops and the clock resets, 70 PPM is reached again, and the clock starts. This cycle can continue for a very long time.
b) 70 PPM is reached and the level increases, but the alarm doesn't sound for up to 4 hours. That is dangerous.

I carry my personal CO detector every day even though like you I'm semi-retired. I've had it alert in commercial kitchens when the exhaust fan is not on. (In the winter)

I understand there worried about false alarms using 30PPM as a threshold but feel the 70PPM up to 4 hours is even worse. The average person thinks the Ul listed alarm will alert them to a dangerous condition in time when in fact the CO levels are already at a dangerous level.71PPM for 4 hours there's damage done!

I have 2 defenders in this house, 1 in the boiler room and 1 on the 2nd floor where the bedrooms are.

GW

WM not the same thing. UL is slow, read the info. If a UL beeps you have issues for sure 

mattmia2

pecmsg said:

wmgeorge said:

Or have a good working CO detector that is how mine was found. In any event the OP needs to be made aware of the issue, like I said before that's old news by now.

Good working are not good enough

Low Level CO detectors that will alarm well before the 70PPM 1- 3-hour delay UL listed models!

That is assuming there is even enough co in the products of combustion to be detected at all after only a small leak and it is diluted with household air that is being replaced by infiltration. It will probably have been there a while by the time you'd detect it with a co monitor.

MikeAtl

We'll I guess this became a CO detector thread.

But back to my original question about Pulse Air Diaphragm assembly interchangeability. I contacted Lennox Support, but they only referred me to a my local Lennox contractor. Not much help for a DIY situation.

Any way, I understand that there is a space/washer inside the assembly and it's model specific. My question is whether the outer plates and fiberglass diaphragm are model specific. I have attached an image of an assembly that looks similar to mine for reference. Thanks.

Also an DIY video... https://www.youtube.com/watch?v=mEUdZFhsMfs

wmgeorge

I live 60 miles from the Lennox plant in Marshalltown Iowa and I owned a pulse for many years. At one time had access to Lennox parts and service material . Yes, they are model specific, replace with the same or a cross over too it. Do you have a local dealer? If so buy from them, they should not have an issue selling to you. Did you ask about the recall and testing? Regardless of the off topic BS on here, take your Model and S/N over to your Dealer and ask them. Take your old flapper assy along also.

MikeAtl

I think I've figured it out. Thanks for your assistance.

WilliamPurcell

Is that you Mike? You really should consider replacing that Pulse with a reliable Carrier model…